Signal strength based indoor and outdoor localization scheme in Zigbee sensor networks

Positioning schemes in sensor networks are presented in this study. A framework monitoring the signal strength based on the transmission protocol AODV and the placement of Zigbees is established and used in sensor node positioning. To treat indoor and outdoor environments, two positioning schemes are presented accordingly. The indoor scheme clusters the localization zone into several subzones based on the strongest received signal, whereas the outdoor scheme adopts the estimated distance to determine the most possible position of the sensed node. Unlike existing studies, our methods do not need any location fingerprinting process in advance or location database. One-floor and multi-floor environment for indoor positioning cases are examined, where the accuracies of different node placements are studied. Two positioning algorithms used in outdoor cases are investigated, where field tests are conducted to evaluate the performance. Results show that the proposed methods can achieve good accuracy in both indoor and outdoor environments.